If the assets were "placed in service" in 2020, then depreciation starts in 2020.  It isn't an option.

If the taxpayer wants to MINIMIZE depreciation, elect out of Bonus depreciation (assuming it qualifies) and maybe change the depreciation to Straight-Line rather than accelerated depreciation.

In the event there is NO earned income on the tax return, using Section 179 would push it all to next year (if the asset qualifies for 179).